This invention relates to a golf ball having a characteristic arrangement of dimples. More particularly, the present invention relates to a golf ball which can secure nearly the same carry or flying distance regardless of the orientation of the ball when hit and which can make it possible to more freely arrange the dimples.
When the dimples are arranged on a spherical surface of a golf ball, the spherical surface is divided into spherical polygons by assuming polyhedrons inscribing the sphere and projecting each polygon constituting the polyhedron on the spherical surface. The dimple arrangement is designed on the basis of these spherical polygons. The polyhedrons may include regular polyhedrons such as a regular octahedron, a regular dodecahedron, a regular icosahedron, etc., and quasi-regular polyhedrons such as a dodeca-icosahedraon (12-20 hedron), a cubic octahedron, etc.
The dimples arranged in this way are generally disposed with a lot of symmetry lines so that the ball has the same carrying properties (flying distance) how the ball is set on the tee (or how the ball lies). This property is sometimes referred to as aerodynamical uniformity.
An example of a prior art golf ball is shown in FIG. 6. In this golf ball, each polygon constituting a 12-20 hedron is projected on the spherical surface 11 and dimples 12 are arranged thereon. The spherical surface 11 is divided into twelve spherical regular pentagons X and twenty spherical regular triangles Y corresponding to the facets of the 12-20 hedron. A plurality of dimples 12 are arranged in each of these spherical regular pentagons X and triangles Y. Six great circle paths (the center of which coincides with the core center of the golf ball) Z which coincide with the dividing lines are disposed on the golf ball. Each of the spherical regular pentagons X and triangles Y respectively employ the same dimple pattern.
In the golf ball of FIG. 6 the dimple pattern is the same when viewed from any side of each spherical regular pentagon X or each spherical regular triangle Y. In other words, in the case of the spherical regular pentagon, the dimple pattern has five symmetry lines passing through the angles of the spherical regular pentagon, respectively, and in the case of the spherical regular triangle, the dimple pattern has three symmetry lines passing through the angles of the spherical regular triangle, respectively.
Accordingly, the dimples arranged on the spherical surface of the golf ball have high symmetricalness, and make it possible to secure generally the same carry irrespective of the setting method of the golf ball. On the contrary, because the limitation exists in that the dimple patterns must be disposed symmetrically, the problem of poor freedom of design of the dimple arrangement is posed.